Multiple Choice Questions on DNA Packaging

Q1. Which of the following statement is true?

a)    Histone proteins are of low molecular weight

b)    Non-histone proteins are of high molecular weight

c)    Both histone and non-histone proteins are of low molecular weight

d)    Both histone and non-histone proteins are of high molecular weight

e)    Both a and b

Q2. Which of the following statement is true?

a)    Histone proteins are basic in nature

b)    Histone proteins are acidic in nature

c)    Non-histone proteins are acidic in nature

d)    Both histone and non-histone proteins are acidic in nature

e)    Both a and c

Q3. Which of the following statements are true?

a)    Histone proteins are rich in lysine and arginine

b)    Lysine and arginine are basic amino acids

c)    Non-histone proteins are rich in tyrosine and tryptophan

d)    Tyrosine and tryptophan are aromatic  amino acids

e)    All of the above

Q4. Out of the five histone proteins, which are rich in lysine and arginine?

a)    H1, H2A, and H2B are rich in lysine and H3 and H4 are rich in arginine

b)    H1, H2A, and H2B are rich in arginine and H3 and H4 are rich in lysine

c)    All five amino acids are rich in lysine

d)    All five amino acids are rich in arginine

Q5. Out of the three types of non-histone proteins, what is the function of structural / scaffold protein?

a)    Scaffold proteins are involved in the packaging of chromatids at a higher level

b)    Help in the replication of DNA

c)    Involved in gene expression

d)    None of the above

Q6. What are the three different types of non-histone proteins involved in DNA packaging?

A)   Structural proteins, scaffold proteins, enzymatic proteins

B)   Scaffold proteins/structural proteins, enzymatic proteins, regulatory proteins

C)   Scaffold proteins, enzymatic proteins, inhibitory proteins

D)   H1, H2A, H2B

E)   H2B, H3, H4

Q7. DNAP and RNAP are examples of:

a)    Structural proteins

b)    Scaffold proteins

c)    Enzymatic proteins

d)    Regulatory proteins

e)    Inhibitory proteins

Q8. Until the time DNA is attached to histone proteins, DNA does not express itself. What happens when regulatory proteins interact with histone proteins?

a)    The regulatory proteins make the histone protein unstable so that they are removed from the DNA

b)    Regulatory proteins help in the expression of DNA

c)    Histone proteins are considered as repressor proteins as they do not allow the DNA to express

d)    Regulatory proteins are also known as derepressor proteins

e)    All of the above

Q9. What is the diameter of a double-stranded DNA?

a)    2 nm

b)    3 nm

c)    2 angstrom

d)    4 nm

e)    None of the above

Q10. Out of the five histone proteins, two molecules of each H2A, H2B, H3 and H4 form a structure called:

a)    Octamer

b)    Nu-body

c)    Core molecule

d)    Hexamer

Q11. How many turns of DNA are present in each octamer?

a)    2 complete turns

b)    1 complete turns and 3/4^th turn

c)    1 complete turn and a half turn

d)    3 complete turns

e)    3 and a half turn

Q12. Which of the following protein is involved in the clipping of DNA ends:

a)    H1

b)    H2A

c)    H3

d)    H4

e)    H2B

Q13. Nucleosome structure is formed by combining:

a)    Octamer and DNA only

b)    Octamer and H1 only

c)    Octamer, DNA and H1

d)    DNA and H1 only

e)    DNA, RNA, Octamer and H1

Q14. What is the diameter and length of the octamer?

a)    10 nm diameter and 6 nm length

b)    6 nm diameter and 10 nm length

c)    10 nm diameter and 7 nm length

d)    7 nm diameter and 10 nm length

e)    None of the above

Q15. How many base pairs of DNA are present in a nucleosome:

a)    300 bp

b)    200 bp

c)    150 bp

d)    400 bp

e)    900 bp

Q16. After the first level of packaging of DNA, beads like strings are seen under the microscope. The diameter of this string is about:

a)    10 nm

b)    15 nm

c)    10.5 nm

d)    15.5 nm

e)    30 nm

Q17. The second coiling of beads like strings forms solenoid structure or chromatin fiber with a diameter of:

a)    30 nm

b)    300 nm

c)    150 nm

d)    15 nm

e)    100 nm

Q18. In chromatin fibre or solenoid, each coil consists of:

a)    2-4 nucleosomes

b)    4 -6 nucleosomes

c)    5-6 nucleosomes

d)    6-8 nucleosomes

e)    10-12 nucleosomes

A19. The third coiling results in the formation of the super solenoid with a diameter of:

a)    200 nm

b)    300 nm

c)    400 nm

d)    500 nm

e)    600 nm

Q20. The fourth level of coiling results in the formation of:

a)    Chromatid with a diameter of 700 nm

b)    Chromatid with a diameter of 1400 nm

c)    Chromosome with a diameter of 700 nm

d)    Chromosome with a diameter of 1400 nm

e)    None of the above

Q21. Two regions are present in DNA i.e., darkly stained and lightly stained. Which of the following statement is true?

a)    The darkly stained region is called heterochromatin and it is transcriptionally active region

b)    The darkly stained region is called euchromatin and it is transcriptionally active region

c)    The light stained region is called euchromatin and it is transcriptionally inactive region

d)    The light region is euchromatin and dark region is heterochromatin where euchromtin is active and hetrochromtin is inactive

e)    All statements are correct

     Answer key: 

1. e

2. e

3. e

4. a

5. a

6. b

7. c

8. e

9. a

10. a

11. b

12. a

13. c

14. a

15. b

16. a

17. a

18. c

19. b

20. a

21. d

Explanation:
Q1. Protein size is measured in Daltons, a measure of molecular weight. One Dalton is defined as the mass of a hydrogen atom, which is 1.66 x 10^-24 grams. Most proteins have masses on the order of thousands of Daltons, so the term KD. The average weight of an amino acid is 110 Daltons – the no, of amino acids can be approximated.  Appropriate molecular weight of protein = no. of amino acids x 110 Daltons